1. Field of Invention
This invention relates to intentional burning for land and forestry management and, in particular, to an apparatus, method and system for launching incendiary projectiles.
2. Description of Related Art
Prescribed burning is the intentional burning of typically forested areas to meet specific land management objectives, such as to reduce flammable fuels, restore ecosystem health, recycle nutrients, or prepare an area for new trees or vegetation.
Devices for igniting prescribed fires include conventional land based and aerial ignition devices. Aerial ignition devices are typically mounted on a helicopter, receive plastic spheres containing an incendiary material, such as potassium permanganate, inject the received spheres with a reactant, such as ethylene glycol, and then expel the injected spheres to fall from the helicopter. A delayed exothermic reaction between the incendiary material and the reactant within the spheres can produce a prescribed fire where the spheres land. The delay of the exothermic reaction is typically 25 to 30 seconds. Significant disadvantages to aerial ignition operations are the cost of operating the aircraft, the need for at least two persons to conduct the burning operations, namely a pilot and an operator for the ignition device, the inherent time delay in getting aerial operations underway as opposed to ground based operations, and the safety risk in having incendiary material being handled in an aircraft.
Conventional land based ignition devices include a conventional hand-held drip torches that drip ignited fuel on the ground as the operator walks along a desired path for the prescribed burn. A disadvantage to these torches is that they require the operator to be at the point of origin of the fire and this poses a significant safety concern. Another disadvantage to hand held drip torches is that the process of igniting a prescribed burn with them is both personnel intensive and time intensive.
Other land based ignition devices include flame throwers. A disadvantage to using flame throwers is that they use a gelled fuel which must be premixed and transported to the site of the prescribed burn. This introduces safety issues and the transport of the gelled fuel is highly regulated. As well, once the fuel is mixed, it must all be used up or otherwise safely disposed, and this means a lack of flexibility as well as economic considerations since the fuel itself is quite costly. In addition, the range of flame thrower, while greater than a hand torch, is still not as far as one would like from a safety perspective. Logistics are also a problem with the use of flame throwers as the gelled fuel requires large mixing and storage tanks which means that large trucks or trailers must be brought into the zone of the prescribed burn, and this limits the terrain on which flame throwers can be used.
Accordingly, it would be desirable to have land based ignition devices, methods and systems that overcome some or all of the disadvantages of the prior art.